Methods and apparatus for synchronizing beacon transmissions in a neighbor awareness network (NAN)

ABSTRACT

The present disclosure describes methods and apparatus for synchronizing beacon transmissions. Synchronization beacons may be transmitted from multiple nodes during a same time slot of a discovery window with accommodation for managing potential signal interference. For certain example embodiments, a first wireless communication device includes a transceiver and a synchronization beacon transmission system. A transceiver may be configured to transmit a synchronization beacon in a neighbor awareness networking (NAN) environment, wherein the NAN environment includes multiple wireless communication devices arranged in a cluster. A synchronization beacon transmission system may be configured to determine a transmission time based at least partially on an operation that separates the wireless communication devices of the cluster into multiple groups. A synchronization beacon transmission system may further be configured to cause the transceiver to transmit the synchronization beacon responsive to the determined transmission time.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims priority to U.S.Utility patent application Ser. No. 14/679,957 filed Apr. 6, 2015, nowU.S. Pat. No. 9,723,582, which in turn claims priority to U.S.Provisional Patent Application Ser. No. 61/976,395 filed Apr. 7, 2014,the disclosure of which is incorporated herein by reference in itsentirety.

BACKGROUND

Wireless interconnectivity is becoming increasingly pervasive in amyriad of devices across many different environments. For example,pursuit of the so-called “internet of things” may result in wirelesscomputing technology being embedded in many different types of objects,such as shoes or refrigerators in consumer environments or such asmanufacturing equipment or inventory management containers in commercialenvironments. As the number and types of objects with a wirelesscommunication ability increase significantly, wireless interconnectivitybetween or among different wireless communication devices may likewisegrow significantly. As a result of this wireless interconnectivitygrowth, various wireless communication devices may have substantiallydifferent native capabilities or may have direct access to dramaticallydifferent network features. If such native capabilities or networkfeatures were to be restricted solely to their respective devices, thepotential benefits of expanding wireless interconnectivity would beappreciably limited.

SUMMARY

In general, in one example aspect, this specification describes a firstwireless communication device for synchronizing beacon transmissions ina neighbor awareness network (NAN). The first wireless communicationdevice includes a transceiver and a synchronization beacon transmissionsystem. The transceiver may be configured to transmit a synchronizationbeacon in a NAN environment, wherein the NAN environment includesmultiple wireless communication devices arranged in a cluster. Thesynchronization beacon transmission system may be configured todetermine a transmission time based at least partially on an operationthat separates the wireless communication devices of the cluster intomultiple groups. The synchronization beacon transmission system mayfurther be configured to cause the transceiver to transmit thesynchronization beacon responsive to the determined transmission time.

In general, in another example aspect, this specification describes amethod for synchronizing beacon transmissions that is implemented with afirst wireless communication device. The method may include determining,in a neighbor awareness networking (NAN) environment that includesmultiple wireless communication devices arranged in a cluster, atransmission time based at least partially on an operation thatseparates the wireless communication devices of the cluster intomultiple groups. The method may also include transmitting asynchronization beacon in the NAN environment responsive to thedetermined transmission time.

In general, in yet another example aspect, this specification describesa computer-readable memory device comprising computer-executableinstructions that, when executed, implement a system for synchronizingbeacon transmissions in a first wireless communication device todetermine, in a neighbor awareness networking (NAN) environment thatincludes multiple wireless communication devices arranged in a cluster,a transmission time based at least partially on an operation thatseparates the wireless communication devices of the cluster intomultiple groups. The system is further implemented to transmit asynchronization beacon in the NAN environment responsive to thedetermined transmission time.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features andadvantages will be apparent from the description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures, the left-most digit of a reference number identifies thefigure in which the reference number first appears. The use of the samereference number in different instances in the description and thefigures indicates like elements.

FIG. 1 depicts an example neighbor awareness networking (NAN)environment that includes wireless communication devices for whichmethods and apparatus for synchronizing beacon transmissions may beimplemented in accordance with one or more example embodiments.

FIG. 2 depicts multiple wireless communication devices that are arrangedto illustrate hops and hop counts in accordance with one or more exampleembodiments.

FIG. 3 depicts a graph having multiple transmitted synchronizationbeacons that may be generated in accordance with one or more exampleembodiments.

FIG. 4 depicts an example arrangement of wireless communication devicesthat may be separated into groups in accordance with one or more exampleembodiments.

FIG. 5 illustrates multiple groups of wireless communication devicesthat may be respectively mapped to multiple time slots respectivelycorresponding to multiple times at which a synchronization beacon may betransmitted in accordance with one or more example embodiments.

FIG. 6 depicts a graph of multiple synchronization beacons thatillustrate a relationship between groups of wireless communicationdevices and transmission times over a discovery window in accordancewith one or more example embodiments.

FIG. 7 is a flowchart illustrating an example process for synchronizingbeacon transmissions in a NAN environment in accordance with one or moreexample embodiments.

FIG. 8 is a flowchart illustrating another example process forsynchronizing beacon transmissions in a NAN environment in accordancewith one or more example embodiments.

FIG. 9 depicts an example device that can implement various aspects ofthe mechanisms and processes described herein.

DETAILED DESCRIPTION

As noted hereinabove, various wireless communication devices may havesubstantially different native capabilities or direct access todramatically different network features. Examples of native capabilitiesmay include processing speed, display size or resolution, agencyauthority or accessibility, installed software, person-machine interfaceoptions, locally-stored data, printing capacity, imaging ability, localauthentication or authorization level, a combination thereof, and soforth. Examples of network features may include network bandwidth,wireless versus wireline, local area network (LAN) versus internet,remotely-relevant authentication or authorization level, access toremotely-stored data, access to shared or server storage, access toremotely-located or so-called cloud services, encrypted communicationcapacity, network latency, access to particular network nodes, unlimitedor metered or capped data, a combination thereof, and so forth.Capabilities and features of devices, whether native or network-based,may be considered examples of services that are usable by other devicesor end-users. Devices that are able to communicate wirelessly can learnto exchange information about, or actually share, services that areprovided or directly-accessible by, or otherwise primarily associatedwith, a given device.

One approach to exchanging information or sharing services over anetwork entails distributing synchronization data to organize wirelesscommunication devices that serve as nodes that form the network.Synchronization data can be used to facilitate a smooth networkoperation as well as information exchange that is efficient from a powerand spectrum perspective. The farther synchronization data can bedistributed, the larger a cluster of devices for a network can grow. Andthe larger a network cluster grows, the more widely can information beexchanged and services be shared via the network cluster. However, ifthe distribution of synchronization data is limited, the benefits ofwireless interconnectivity may be geographically curtailed or otherwiselimited.

One approach to distributing synchronization data may involvetransmission of synchronization beacons. Due to the finite nature of theelectromagnetic spectrum and a desire to prioritize transmission ofuser-related data, transmission of synchronization beacons may beassigned to a particular channel and time window. Unfortunately,assignment to a particular channel and time window may result in afinite time span in which to transmit synchronization beacons. Multiplesynchronization beacons may be transmitted within a single time slot ofmultiple time slots of the finite time span, but many synchronizationbeacons may be lost due to cross interference arising from simultaneoustransmission. Hence, this finite time span may translate into acorresponding finite number of synchronization beacons if contention isto be avoided by assigning each synchronization beacon an individualtime slot (e.g., if non-overlapping sequential transmission ofsynchronization beacons is implemented across a finite time span).Unfortunately, if synchronization beacons are constrained to a finitenumber, a size of a network cluster is also constrained inasmuch as onlya finite number of nodes may transmit synchronization beacons.

On the other hand, a technique that enables a theoretically unlimitednumber of synchronization beacon transmissions within a finite-sizedwindow effectively increases a feasible size of a network cluster.Hence, implementation of a technique to enable unlimited transmission ofsynchronization beacons within a finite-sized window may also increase afeasible scope and range of information exchanging and service sharingfor a network cluster of wireless communication devices. This in turnmay help fulfill the promise of expanding wireless interconnectivity.

For certain example embodiments, different implementations or aspects ofsynchronization beacon transmission are described herein. By way ofexample only, wireless communication devices may be separated intogroups based at least partly on relative distances between or among thewireless communication devices (e.g., separated into groups that arelikely sufficiently far apart from one another so as to reduce aprobability of signal interference). To avoid having a width of afinite-sized window act as a limiting factor for synchronization beacontransmission, multiple synchronization beacons may be transmittedsimultaneously or at times that at least partially overlap forrespective multiple wireless communication devices that are separatedinto a single group. Hop count values, for instance, may be used as anindicator of relative distances between or among the wirelesscommunication devices.

Synchronization beacon transmission may be implemented in a neighborawareness networking (NAN) environment. NAN, as used herein, may referto exchanging via wireless network communication information about, oractually sharing, services that are provided or directly-accessible by,or otherwise primarily associated with, a given device. By way ofexample only, NAN may enable a refrigerator to find a device offeringinternet access to enable the refrigerator to send an updated list ofgrocery items that need to be purchased by a home owner. As anotherexample, NAN may enable a printer to advertise a capability to provide ahard copy of: (i) a grocery list for a refrigerator, (ii) a guide ofavailable media options during a Friday evening viewing period for asmart television, (iii) a student's project for a school-issued laptop,and so forth. NAN may include, but is not limited to, so-called “Wi-FiAware” technology of the Wi-Fi Alliance, a social announcement scheme toenable discovery or advertising of one or more services that may beshared between or among two or more wireless communication devices viaat least one announcement operation or message, or combinations thereof.

In one or more example embodiments as described herein, transmission ofsynchronization beacons with NAN technology may use, or may beimplemented in conjunction with or in an environment involving, at leastone communication protocol that is compliant with Wi-Fi networking, suchas a network implementing or comporting with at least a portion of anIEEE 802.11 standard (e.g., as discussed in the IEEE Std. 802.11-2012,Mar. 29, 2012). Nevertheless, although reference may be made herein toan IEEE 802.11 standard or various aspects thereof (e.g., channels,frequencies, message or frame types, air interface guidelines, orprotocol specifications), the techniques and approaches described hereinmay additionally or alternatively be implemented using one or more other(e.g., wireless) standards or signaling technologies.

For certain example embodiments, wireless communication devices thatimplement NAN may be organized into clusters. A NAN-implementing devicemay participate in one or more NAN clusters. A device may leave or moveto or join a given cluster depending on preferences or current servicedesires of the device. NAN may provide a mechanism for devices tosynchronize a time or a channel on which they converge to facilitatediscovery of services that have been made discoverable by existingdevices of a cluster or by new devices that enter a NAN environment. NANdevices may share a common set of NAN parameters, such as: a timeduration of a discovery window (DW), a time period between consecutivediscovery windows, a beacon interval, NAN Channel(s), combinationsthereof, and so forth. Depending on changes to a NAN cluster, includingbut not limited to changes in which NAN devices are part of a NANcluster or which NAN devices have what master ranks, different NANdevices may be elected to become a NAN device having a master role atvarying times. Examples of roles within NAN environments are describedherein below with particular reference to FIG. 2.

FIG. 1 depicts an example neighbor awareness networking (NAN)environment 100 that includes wireless communication devices 102 forwhich methods and apparatus for synchronizing beacon transmissions maybe implemented in accordance with one or more example embodiments. Asillustrated, example NAN environment 100 includes multiple wirelesscommunication devices (WCDs) 102, each of which may include at least onetransceiver (TRX) 104 and at least one synchronization beacontransmission system 106. A wireless communication device 102 maycomprise any object that includes a wireless capability, such as a fixedstation, a mobile station, a handset, a system on a chip (SoC), acombination thereof, and so forth. Additional examples of, anddescription of various components for, a wireless communication device102 are provided herein below with particular reference to FIG. 9.

As shown, there are four wireless communication devices 102(0), 102(1),102(2), and 102(3) depicted in a clockwise order starting from the topleft corner. A wireless communication device 102(0) may include at leasta transceiver 104(0) and a synchronization beacon transmission system106(0). A wireless communication device 102(1) may include at least atransceiver 104(1) and a synchronization beacon transmission system106(1). A wireless communication device 102(2) may include at least atransceiver 104(2) and a synchronization beacon transmission system106(2). And a wireless communication device 102(3) may include at leasta transceiver 104(3) and a synchronization beacon transmission system106(3). Although four wireless communication devices 102 arespecifically shown by way of example in FIG. 1, one, two, three or morewireless communication devices 102 may generally operate in a NANenvironment 100 to facilitate synchronization beacon transmission.

For certain example embodiments, synchronization beacon transmissionfunctionality may be distributed between or among one or more wirelesscommunication devices 102, such as wireless communication devices102(0), 102(1), 102(2), or 102(3). Different one(s) of wirelesscommunication devices 102 may perform particular functionalityindividually or jointly at various times. Descriptions herein generallyrelate to functionality being distributed among each of wirelesscommunication devices 102(0), 102(1), 102(2), and 102(3). Alternatively,in some situations functionality may be distributed between or amongcertain wireless communication device(s) 102 but omitted from or latentin other ones (e.g., included in ones with a relatively recent protocolversion or with a current synchronization role, but omitted from oneswith a relatively older protocol version or latent in ones without acurrent synchronization role).

For certain example implementations, a transceiver 104 may include atransmitter, a receiver, both a transmitter and a receiver, logic tooperate a transmitter or receiver in accordance with (e.g., one or morephysical, data link, or network layers of) at least one wirelessstandard for propagating signals, a receiver chain, a frequencyconverter, a filter, some combination thereof, and so forth. A wirelesscommunication device 102 may be capable of transmitting a wirelesssignal, receiving a wireless signal, both transmitting and receivingwireless signals, or some combination thereof using a transceiver 104via at least one wireless channel. A synchronization beacon transmissionsystem 106 may be configured to process signals that have been receivedor that are to be transmitted via a transceiver 104, including but notlimited to those signals that facilitate or otherwise pertain to asynchronization beacon transmission scheme. Signal processing mayinclude, but is not limited to, interpreting, decoding, formulating,generating, calculating values based on, responding to, or a combinationthereof one or more signals. For certain example embodiments, asdescribed further herein, a synchronization beacon transmission system106 may use one or more indicators of relative distance between or amongother wireless communication devices 102 to determine timings fortransmitting synchronization beacons.

FIG. 2 depicts at 200 generally multiple wireless communication devices102 that are arranged to illustrate hops 208 and hop counts 210 inaccordance with one or more example embodiments. Depicted generally at200 are four wireless communication devices 102, multiple roles 202 and204, four wireless signals 206, four hops 208, and four hop counts 210.More specifically, the following are depicted: wireless communicationdevices 102(0), 102(1), 102(2), and 102(3); an anchor master role 202and a synchronization role 204; hops 208(1), 208(2), 208(3), and 208(4);and hop counts 210(0), 210(1), 210(2), and 210(3). Although fourwireless communication devices 102, four hops 208, four hop counts 210,etc. are explicitly shown in FIG. 2, fewer or more than four mayalternatively be involved in a given implementation. Also, althoughwireless communication devices 102(0), 102(1), 102(2), and 102(3) andwireless signals 206 are depicted linearly in FIG. 2 for the sake ofvisual simplicity and to facilitate understanding, wirelesscommunication devices 102 may be located in one or more differentgeographical arrangements in an actual implementation (e.g., devices 102may be in a zig-zag pattern, devices 102 may have different elevations,or devices 102 may be scattered randomly).

For certain example embodiments, each wireless communication device 102is in communication with at least one other wireless communicationdevice 102 via a wireless signal 206. For instance, wirelesscommunication device 102(0) may transmit a wireless signal 206 to bereceived by wireless communication device 102(1), and wirelesscommunication device 102(3) may receive a wireless signal 206 that wastransmitted by wireless communication device 102(2). As shown, wirelesscommunication device 102(0) is associated with an anchor master role202, and wireless communication devices 102(1), 102(2), and 102(3) areassociated with a synchronization role 204. A hop count equal to zero,HC=0 210(0), may be assigned to a wireless communication device 102(0)having a synchronization anchor master role 202.

Role association may be transient or vary over time for any givenwireless communication device 102. Generally, roles may be segregatedinto master roles and non-master roles. A master role may correspond to,by way of example but not limitation, an anchor master role 202 or astandard master role (not explicitly illustrated). A non-master role maycorrespond to, by way of example but not limitation, a non-mastersynchronization role or a non-master non-synchronization role. Forcertain example environments, a role that is associated with a wirelesscommunication device 102 may control (or at least affect) which one ormore beacon types, if any, the wireless communication device (i) ispermitted to generate or transmit or (ii) is responsible for generatingor transmitting. Types of beacons may include, by way of example butwithout limitation, discovery beacons and synchronization beacons. Adiscovery beacon may be used to announce (e.g., advertise or discover)services that are made available by or desired by one or more wirelesscommunication devices of a given cluster. A synchronization beacon maybe used to distribute a time indicator between or among various wirelesscommunication devices to facilitate temporal synchronization.

For certain example embodiments, a wireless communication device havinga master role (e.g., an anchor master role 202 or a standard masterrole) may have an authority or a responsibility to transmit a discoverybeacon or a synchronization beacon for a cluster of wirelesscommunication devices. An anchor master role 202, in particular, mayfurther entail an authority or a responsibility to establish asynchronization time for a cluster. A wireless communication devicehaving a non-master synchronization role may have an authority or aresponsibility to transmit a synchronization beacon but not a discoverybeacon for a cluster. And a wireless communication device having anon-master non-synchronization role may lack an authority or aresponsibility to transmit either a synchronization beacon or adiscovery beacon. A synchronization role 204 may refer to an authorityor a responsibility to transmit at least a synchronization beacon aseither a master or a non-master (e.g., as a standard master role or anon-master synchronization role). Wireless communication device 102(0),which is associated with an anchor master role 202, may transmit asynchronization beacon and establish a timing synchronization for acluster. Wireless communication devices 102(1), 102(2), and 102(3),which are associated with a synchronization role 204, may transmitsynchronization beacons.

Wireless communication device 102(0), which is associated with an anchormaster role 202, corresponds to a hop count 210(0) value of zero. Thereis one hop 208(1) between wireless communication device 102(0) and102(1). Hence, wireless communication device 102(1) corresponds to anincremented hop count 210(1) value of one. Thus, there is a hop 208(1)between wireless communication device 102(0) and 102(1), a hop 208(2)between wireless communication device 102(1) and 102(2), a hop 208(3)between wireless communication device 102(2) and 102(3), and so forth.Consequently, wireless communication device 102(0) has a hop count210(0) of zero, wireless communication device 102(1) has a hop count210(1) of one, wireless communication device 102(2) has a hop count210(2) of two, wireless communication device 102(3) has a hop count210(3) of three, and so forth.

For certain example embodiments, hops 208 and hop counts 210 may be atleast initially established based on an indicator of distance betweentwo or more wireless communication devices 102. A distance may bedetermined, by way of example only, by sharing individual physicalpositioning data (e.g., GPS coordinates), exchanging wirelesscommunications, or a combination thereof. A wireless signal may bepropagated between a first and a second wireless communication device(e.g., transmitted by one and received by another). For instance, awireless signal 206 may be propagated between wireless communicationdevice 102(2) and wireless communication device 102(3). In an IEEE802.11 environment, for example, a wireless signal 206 may comprise ormay carry or may be part of at least one frame (e.g., an action frame, amanagement frame, a beacon frame, or a combination thereof).

One example technique to determine a distance between two wirelesscommunication devices relies on estimating distance from a receivedsignal strength indication/indicator (RSSI) corresponding to a wirelesssignal 206. Generally, a stronger RSSI correlates to a shorter distanceindicator, depending on initial transmission strength and one or morebarriers to signal propagation. Another example technique to determine adistance between two wireless communication devices is Wireless LocationServices (WLS), which is a burgeoning 802.11 protocol. With WLS, but byway of example only, two wireless communication devices may sendmanagement frames to each other and record a time at which the frameswere sent and received. A time of flight (ToF) of at least one frame ofone or more exchanged frames may be calculated from recorded timestampdata. A distance indicator between two wireless communication devicesmay be generated using a time of flight of one or more exchanged frames.A distance indicator with WLS may be accurate, for instance, to withinapproximately three (3) centimeters (cm).

FIG. 3 depicts a graph 300 having multiple transmitted synchronizationbeacons 306 that may be generated in accordance with one or more exampleembodiments. For graph 300, time (t) elapses along the abscissa axis302, and transmission of wireless signals is indicated along theordinate axis 304. As illustrated, graph 300 includes multiplesynchronization beacons 306 and a discovery window (DW) 312. An examplesynchronization beacon 306 is shown to include a time indicator 308 anda hop count indicator 310.

For certain example embodiments, a discovery window 312 occupies asegment of time 302. A width of a discovery window 312 defines a finiteperiod of time during which beacons, such as synchronization beacons306, may be transmitted and received by wireless communication devicesof a given cluster. Discovery windows 312 may occur at a known ordeterminable frequency to facilitate the distribution of timinginformation and therefore the synchronization of wireless communicationdevices in a given cluster.

A synchronization beacon 306 may include any number of fields in anyorder. Two example fields are shown in an example order: time indicator308 and hop count indicator 310. A time indicator 308 may provide a timesynchronization value. By way of example only, a time indicator 308 maycomprise a timestamp produced in accordance with a timingsynchronization function (TSF). A hop count indicator 310 may provide aninteger hop count value, such as a hop count 210 (e.g., at least of FIG.2). By way of example only, a hop count indicator 310 of a receivedsynchronization beacon 306 may reflect a hop count of a wirelesscommunication device that is one-hop closer to an anchor master than awireless communication device that received the synchronization beacon,and a hop count indicator 310 of a transmitted synchronization beacon306 may reflect a hop count of the transmitting wireless communicationdevice.

If each synchronization beacon 306 were to be respectively transmittedin an individual, non-overlapping time slot during a discovery window312 of a finite width, then a number of possible synchronization beacons306 would likewise be finite. As discussed hereinabove, limiting anumber of synchronization beacons 306 also limits a number of hop countsand therefore a potential size of a cluster of wireless communicationdevices. If synchronization beacons 306 were permitted to be transmittedwithout any constraint to their timing or location of emanation, thenmultiple synchronization beacons 306 would likely collide and fail toproperly distribute a time indicator 308 for temporal synchronizationpurposes. If, on the other hand, a technique enabled multiplesynchronization beacons 306 to be transmitted substantiallysimultaneously while reducing a likelihood of collision or mutualinterference, then a potential size of a cluster of wirelesscommunication devices may be increased.

FIG. 4 depicts an example arrangement 400 of wireless communicationdevices 102 that may be separated into groups 402 in accordance with oneor more example embodiments. As illustrated, arrangement 400 includesnine wireless communication devices 102, nine hop counts 210 (e.g.,“{HC=# }”), and three groups 402, as well as a number of arrows mappingdevices to groups. More specifically, nine wireless communicationdevices 102(0), 102(1), 102(2), 102(3), 102(4), 102(5), 102(6), 102(7),and 102(8) and three groups 402(1), 402(2), and 402(3) are shown.Although nine wireless communication devices 102 and three groups 402are explicitly shown in FIG. 4, more or fewer devices or groups mayalternatively be involved in a given implementation.

Generally, as a distance between two wireless communication devices 102increases, a likelihood of one device's transmission interfering withanother device's transmission decreases. Consequently, as a distancebetween two wireless communication devices 102 increases, it becomesrelatively safer for both to transmit a synchronization beacon during asame time slot. Wireless communication devices 102 that aregeographically separated may be separated into groups 402 that are, forexample, permitted to transmit synchronization beacons during a singletime slot. As noted above, an indicator of a distance between twowireless communication devices 102 may be determined (i) from absolutepositional data (e.g., GPS coordinates) or (ii) relatively using, forinstance, RSSI or WLS. As is explained below, another example indicatorof distance between two wireless communication devices 102 is hop countvalues or a differential derived from hop count values.

For certain example embodiments, wireless communication devices 102 maybe separated into groups 402 based at least partially on hop countvalues. For example, a separation operation may include an operation inwhich every nth wireless communication device 102 may be separated into(e.g., assigned to) a same group 402. Additionally or alternatively,group assignment may be based at least partially on a result of anoperation in which a hop count is subject to a modulus operator, inwhich a hop count is hashed into a group, some combination thereof, andso forth.

As illustrated in the example arrangement 400, every 3rd wirelesscommunication device 102 may be separated into a same group 402 based atleast partially on a hop count 210 value that is respectively associatedwith each wireless communication device 102. More specifically, wirelesscommunication devices 102(1), 102(4), 102(7), etc. are respectivelyassociated with hop counts of one, four, seven, etc. As represented bydotted and dashed arrows 404, wireless communication devices 102(1),102(4), 102(7), etc. may be separated into a Group 1 402(1). Wirelesscommunication devices 102(2), 102(5), 102(8), etc. are respectivelyassociated with hop counts of two, five, and eight. As represented bydashed arrows 406, wireless communication devices 102(2), 102(5),102(8), etc. may be separated into a Group 2 402(2). Wirelesscommunication devices 102(3), 102(6), etc. are respectively associatedwith hop counts of three, six, etc. As represented by solid-lined arrows408, wireless communication devices 102(3), 102(6), etc. may beseparated into a Group 3 402(3). Wireless communication device 102(0),as a master anchor device with an associated hop count of zero, may beindependent of other wireless communication devices 102, whichindependence may be considered a separation into its own group (or nogroup).

FIG. 5 illustrates at 500 generally multiple groups 402 of wirelesscommunication devices 102 that may be respectively mapped 504 tomultiple time slots 502 respectively corresponding to multiple times atwhich a synchronization beacon 306 may be transmitted in accordance withone or more example embodiments. As illustrated, FIG. 5 includes asynchronization master wireless communication device 102(0), threegroups 402 having multiple wireless communication devices 102, a graph300 having multiple synchronization beacons 306, and multiple mappings504 between (i) groups 402 and (ii) time slots 502 or correspondingsynchronization beacons 306. Graph 300 includes a time axis 302 versus atransmission axis 304. Along time axis 302, a discovery window 312 isindicated. Within discovery window 312, multiple time slots 502 areindicated. Although ten wireless communication devices 102, tensynchronization beacons 306, and three groups 402 are explicitly shownin FIG. 5, more or fewer devices, beacons, or groups may alternativelybe involved in a given implementation.

Multiple synchronization beacons 306 are graphed along time axis 302.More specifically, synchronization beacon 306*; synchronization beacons306(1), 306(4), and 306(7); synchronization beacons 306(2), 306(5), and306(8); synchronization beacons 306(3), 306(6), 306(9); and so forth areshown. Multiple groups 402 are associated with multiple wirelesscommunication devices 102 that have been assigned thereto. Morespecifically, Group 1 402(1) is associated with wireless communicationdevices 102(1), 102(4), 102(7), etc.; Group 2 402(2) is associated withwireless communication devices 102(2), 102(5), 102(8), etc.; Group 3402(3) is associated with wireless communication devices 102(3), 102(6),102(9), etc.; and so forth.

For certain example embodiments, a synchronization beacon 306* thatcorresponds to a synchronization anchor master wireless communicationdevice 102(0) may be transmitted at a start time of a discovery window312 or at a time that is distinct from other synchronization beacons306. In contrast, multiple synchronization beacons 306 may betransmitted during other time slots 502. By way of example only, twoembodiments for a time slot (TS) 502 are shown. For the time slot 502that is pictured on the left, one or more synchronization beacons 306may be transmitted during an internal portion of time slot 502 (e.g.,approximately in the middle of time slot 502). For the time slot 502that is pictured on the right, one or more synchronization beacons 306may be transmitted at an edge portion of time slot 502 (e.g.,approximately at the end of time slot 502). A time slot 502 maycorrespond to a (e.g., instantaneous) time or a time range. Moreover,time slots 502 may be defined with alternative widths, with differentguard or buffer periods between consecutive time slots 502, with respectto other placements of synchronization beacons 306, some combinationthereof, etc. in other embodiments.

In an example operation for one or more embodiments, a synchronizationanchor master wireless communication device 102(0) may be mapped 504 toa synchronization beacon 306* or a time corresponding thereto, such asto an initial time slot 502 (not explicitly shown) or a start time of adiscovery window 312. For other wireless communication devices 102,groups 402, which are associated with multiple wireless communicationdevices 102, may be respectively mapped 504 to synchronization beacons306 or times corresponding thereto, such as to time slots 502 as shown.For instance, for Group 1 402(1): wireless communication device 102(1)may be mapped 504 to a transmission time for synchronization beacon306(1), wireless communication device 102(4) may be mapped 504 to atransmission time for synchronization beacon 306(4), wirelesscommunication device 102(7) may be mapped 504 to a transmission time forsynchronization beacon 306(7), and so forth. In other words, wirelesscommunication devices 102 that are separated into Group 1 402(1) (e.g.,wireless communication devices 102(1), 102(4), 102(7), etc.), may bemapped to a same transmission time, such as a same time slot 502.Although each of wireless communication devices 102(1), 102(4), 102(7),etc. may transmit a respective synchronization beacon 306 atsubstantially a same time, a likelihood of interference is reducedinasmuch as some distance physically separates the devices. By way ofexample only, a physical distance of separation may be related to a hopcount differential between wireless communication devices 102 (e.g.,three hops in the examples of FIGS. 4 and 5).

As discussed above, a hop count may be correlated to how far away a nodeis to an anchor master node, as well as how far apart a given node is toone or more other nodes along a hop count chain. For example, a nodeassociated with a hop count of one may be sufficiently distant from anode having a hop count of six that temporally-overlapping transmissionsare unlikely to mutually interfere with one another. These two nodes,with example hop counts of one and six, may therefore be able totransmit their respective synchronization beacons substantiallysimultaneously without adversely impacting distribution of temporalsynchronization data for a cluster of nodes.

For certain example embodiments, a hop count of a wireless communicationdevice (e.g., for hop counts greater than zero) may be modded (e.g.,subjected to a modulus/modulo mathematical or logical operation) into agrouping characteristic or distance separation factor, which groupingcharacteristic/distance separation factor is represented by a variable“Z” herein. A hop count of zero (i.e., HC=0) may be reserved for ananchor master wireless communication device. Transmission times forsynchronization beacons may be determined in accordance with thefollowing Equation (1), which has two portions—Equation (1a) andEquation (1b):

For a hop count of zero (HC=0), a transmission time may be determinedfrom:T _(pkt)(p)=TStartDW;and  (1a)

for a hop count greater than zero (HC>0), a transmission time may bedetermined from:T _(pkt)(p)=TStartDW+[((HC−1)% Z)+1]*40*aSlotTimeT(pk),  (1b)wherein “T_(pkt)(p)” represents a transmission time for asynchronization beacon—which may have a value that comprises a relativeoffset time and be offset from a start time of a discovery window,“TStartDW” represents a start time of a discovery window—which may havea value that is relative to a cluster synchronized time, “HC” representsa hop count value (e.g., for a wireless communication device that iscalculating a transmission time), “Z” represents a distance separationfactor or grouping characteristic, “aSlotTimeT(pk)” represents a lengthof time to at least partially buffer or guard consecutivesynchronization beacons. The operator “%” represents a modulus or modulooperation. By way of example only, a value for “aSlotTimeT(pk)” may benine micro-seconds (9 μs).

FIG. 6 depicts a graph 600 of multiple synchronization beacons 306 thatillustrate a relationship between groups of wireless communicationdevices and transmission times over a discovery window in accordancewith one or more example embodiments. As illustrated, graph 600 includesfour abscissa axes representing elapsed time (T), two ordinate axesrepresenting transmissions, multiple synchronization beacons 306, fivegroups 1-5 of synchronization beacons that are spread at least partiallyacross a discovery window, and multiple hop count indications (e.g.,“{HC=#}”). As shown, a discovery window has edges marked by “T_DW_Start”and “T_DW_End.” Although five groups are shown in FIG. 6 and discussedbelow, more or fewer groups may be created or present in actualimplementations.

By way of example only, a distance separation factor or groupingcharacteristic (e.g., the variable “Z” in Equation (1b) above) is set tofive (5) in this example. Consequently, five groups are shown. Inaddition to a synchronization anchor master wireless communicationdevice having a hop count of zero in the top left of graph 600, thereare “N” wireless communication devices 1, 2, 3 . . . N−1, N that areassociated with a synchronization role (e.g., synchronization role 204of FIG. 2), with “N” representing a positive integer. “N” wirelesscommunication devices 1, 2, 3 . . . N−1, N respectively correspond to“N” hop counts 1, 2, 3 . . . N−1, N. After at least application of theexample transmission time Equation (1b), wireless communication devices102 may be separated into groups with corresponding transmission timesaccording to their associated hop counts as follows: Group 1 isassociated with hop counts of 1, 6, 11 . . . N−4; Group 2 is associatedwith hop counts of 2, 7, 12 . . . N−3; Group 3 is associated with hopcounts of 3, 8, 13 . . . N−2; Group 4 is associated with hop counts of4, 9, 14 . . . N−1; and Group 5 is associated with hop counts of 5, 10,15 . . . N. Thus, a number of hop counts and correspondingsynchronization beacons need not be limited solely by a finite width ofa discovery window.

FIG. 7 is a flowchart illustrating an example process 700 forsynchronizing beacon transmissions in a NAN environment in accordancewith one or more example embodiments. Process 700 is described in theform of a set of blocks 702-704 that specify operations that may beperformed; however, operations are not necessarily limited to the ordershown in FIG. 7 or described herein, for the operations may beimplemented in alternative orders or in fully or partially overlappingmanners. Operations represented by the set of blocks in process 700 maybe performed by a wireless communication device 102, such as a wirelesscommunication device 102(0), 102(1) . . . 102(9) (e.g., of at least FIG.1, 2, 4, or 5).

For certain example embodiments, a transceiver (e.g., a transceiver 104of at least FIG. 1 or 9) may at least partially perform operation(s) ofblock 704, and a synchronization beacon transmission system (e.g., asynchronization beacon transmission system 106 of at least FIG. 1 or 9)may at least partially perform operation(s) of block 702 or 704.

At block 702, a transmission time may be determined based at leastpartially on an operation that separates wireless communication devicesof a cluster into multiple groups. For example, a synchronization beacontransmission system 106 may determine (e.g., compute, calculate, consulta look-up table, a combination thereof) a transmission time (e.g., atime slot 502, a portion of a discovery window 312, a time relative to acluster synchronization time, a time that is offset from a start time ofa discovery window 312, a combination thereof) based at least partiallyon (e.g., using, responsive to, generated from a result of, derived fromdata associated with, or combination thereof) an operation (e.g., aformulaic action, a calculation, an algorithm, a comparison, anassignment, or a combination thereof) that separates (e.g., segregates,assigns, apportions, allocates, organizes, or a combination thereof)wireless communication devices (e.g., wireless communication devices102) of a cluster (e.g., a collection of devices in a NAN environment, anumber of devices having a same anchor master to establish a temporalsynchronization, a self-organized set of devices, or a combinationthereof) into multiple groups (e.g., groups 402).

At block 704, a synchronization beacon may be transmitted responsive toa determined transmission time in a neighbor awareness networking (NAN)environment. For example, a synchronization beacon (e.g., asynchronization beacon 306, one or more frames facilitating temporalsynchronization for a cluster, a wireless signal 206 having a timeindicator 308 for a NAN environment, or a combination thereof) may betransmitted (e.g., sent over a wireless interface, emanated from anantenna, coupled to a radio or antenna, or a combination thereof) by atransceiver 104 in conjunction with synchronization beacon transmissionsystem 106 responsive to (e.g., as a result of, in accordance with,substantially matching, using a value associated with, or a combinationthereof) a transmission time (e.g., a time slot 502, a portion of adiscovery window 312, a time relative to a cluster synchronization time,a time that is offset from a start time of a discovery window 312, acombination thereof) in a NAN environment (e.g., a communicationenvironment in which two or more wireless communication devices exchangeinformation about, or actually share, services that are provided ordirectly-accessible by, or otherwise primarily associated with, a givendevice).

FIG. 8 is a flowchart illustrating another example process 800 forsynchronizing beacon transmissions in a NAN environment in accordancewith one or more example embodiments. Process 800 is described in theform of a set of blocks 802-806 that specify operations that may beperformed; however, operations are not necessarily limited to the ordershown in FIG. 8 or described herein, for the operations may beimplemented in alternative orders or in fully or partially overlappingmanners. Operations represented by the set of blocks in process 800 maybe performed by a wireless communication device 102, such as a wirelesscommunication device 102(0), 102(1) . . . 102(9) (e.g., of at least FIG.1, 2, 4, or 5).

For certain example embodiments, a synchronization beacon transmissionsystem (e.g., a synchronization beacon transmission system 106 of atleast FIG. 1 or 9) may at least partially perform operation(s) of block802, 804, or 806. Process 800 may serve as an example embodiment forblock 702 of process 700 (e.g., of FIG. 7). At block 802, a groupingcharacteristic/distance separation factor may be obtained for a cluster.For example, a value that indicates (i) a number of groups for a clusteror (ii) a (e.g., minimum) number of hops between two wirelesscommunication devices that are to substantially simultaneously transmitsynchronization beacons may be received via a wireless signal (e.g., ifthe value varies by cluster) or retrieved from memory (e.g., if there isat least a specified default value stored for a standard).

At block 804, a hop count may be obtained for a wireless communicationdevice with respect to a synchronization anchor master wirelesscommunication device for a cluster. For example, a number of hops thatseparates a given wireless communication device and an anchor masterwireless communication device for a cluster may be received via awireless signal (e.g., from a device that is one hop closer) orcalculated (e.g., by incrementing a received hop count value) orretrieved from memory (e.g., if previously determined). At block 806, atime for transmission of a synchronization beacon by a wirelesscommunication device may be computed based at least partially on (i) agrouping characteristic and (ii) a hop count. For example, a time, suchas a time slot or a time calculated relative to a discovery window starttime, at which a wireless communication device is to transmit asynchronization beacon may be computed using a grouping characteristic,such as is represented by the variable “Z” in Equation (1b) above, andusing a hop count, such as is represented by the variable “HC” inEquation (1b) above.

The example techniques and approaches described herein support variousdifferent usage scenarios. For example, as noted herein above, exampletechniques and approaches may be implemented in a Wi-Fi scenario. Morespecifically, but by way of example only, they may be implemented inWi-Fi networks in which neighbor awareness networking (NAN) is beingutilized in accordance with so called “Wi-Fi Aware” technology. With NANgenerally, and “Wi-Fi Aware” technology specifically, social networkingmay be at least partially standardized or synchronized so as tofacilitate relatively faster, more power efficient, or more certaindiscovery or advertising of services within direct or indirect radiorange of a given wireless node.

In one or more example usage scenarios, certain example embodiments forsynchronization beacon transmission may enable a more efficient usage ofa wireless medium inasmuch as distance-based grouping of wirelesscommunication devices facilitates simultaneous transmissions ofsynchronization beacons while managing signal contention. Moreover, anumber of hop counts that may be included within a discovery window isnot limited by a width of the discovery window. In other words, atemporal length of a discovery window does not institute a hard cap on anumber of synchronization beacons that may be transmitted during thediscovery window. Consequently, more wireless communication devices mayserve as beacon-transmitting synchronization devices within a givencluster, and the given cluster is therefore enabled to grow larger andthus share services over a greater distance or a greater number ofdevices.

Grouping wireless communication devices based on a distance indicatorfor purposes of transmitting synchronization beacons is described hereinabove for certain example embodiments as being applicable in a NANcontext. However, wireless communication device grouping is not solimited. For example, in addition to also being applicable outside ofNAN environments, grouping of wireless communication devices based on adistance indicator may also or instead be applied to transmission ofother signals.

FIG. 9 depicts an example device 900 that can implement various aspectsof the mechanisms and processes described herein. For certain exampleembodiments, device 900 may be realized as any one or more of a varietyof different devices, including but not limited to, a media device, acomputer device, a television set-top box, a video processing and/orrendering device, an Ethernet interface, a switch, an access point (AP),a home appliance device, a gaming device, an electronic device, avehicle, a workstation, a smart phone, a tablet, a printer, a homeautomation device, a security or safety device such as a camera or afire detector or a door lock, a wearable such as a smart watch orintelligent glasses or a jacket or bag, a Wi-Fi chip, another type ofcomputing device, or some combination thereof. Device 900 may beimplemented as a System-on-Chip (SoC).

For certain example implementations, device 900 may include electroniccircuitry, which has at least one hardware component or tangible aspect;at least one microprocessor; at least one memory; input-output (I/O)logic control; one or more modules; one or more communication interfacesor components; other hardware, firmware, or software applicable toenabling a device to function; some combination thereof; and so forth.Device 900 may also include at least one internal (e.g., integrated)data bus (not explicitly shown in FIG. 9) that couples variouscomponents of the device for data communication between or among thevarious components. A wireless communication device that comprisesdevice 900 or includes device 900 as a sub-part thereof may beimplemented with many combinations of differing components.

Continuing with FIG. 9, example device 900 as illustrated may includevarious components such as an input-output (I/O) logic control 902(e.g., which may include electronic circuitry) or a microprocessor 904(e.g., at least one of a microcontroller, a digital signal processor(DSP), a power-efficient mobile-oriented processing unit, or acombination thereof). Device 900 may also include at least one memory906, which may include any one or more types of memory, such as randomaccess memory (RAM), low-latency nonvolatile memory (e.g., Flashmemory), read only memory (ROM), one-time programmable memory, othersuitable electronic or solid state data storage, some combinationthereof, and so forth. By way of example only, memory 906 may includeone or more tangible or non-transitory storage media. Additionally oralternatively, device 900 may include a memory interface for accessingsupplementary or removable or expandable off-chip memory, such as anexternal Flash memory module.

Device 900 may also include various stored, executable, or executingfirmware or software, such as an operating system 908, which may includecomputer-executable instructions maintained by memory 906 and executedby microprocessor 904. Device 900 may also include other variouscommunication interfaces; communication components; other hardware,firmware, or software; some combination thereof; and so forth. Anexample of one or more communication components may include, but is notlimited to, at least one transceiver (TRX) 104 (e.g., which is describedherein above with particular reference to at least FIG. 1).

Example device 900 may also include a synchronization beacontransmission system 106 that enables at least some synchronizationbeacon transmission techniques to be implemented as described herein. Asynchronization beacon transmission system 106 is explicitly illustratedin FIG. 1. However, various example embodiments or implementationaspects of a synchronization beacon transmission system 106 aredescribed hereinabove with reference to any one or more of FIGS. 1-8. Asynchronization beacon transmission system 106 may be implemented inhardware, firmware, software, combinations thereof, and so forth.

One or more of the example methods or techniques or processes that aredescribed hereinabove may take the form of at least one computer programproduct that is accessible from a computer-usable or computer-readablemedium providing program code for use by or in connection with acomputer or another processing device or any instruction executionsystem. For purposes of this description, a computer-usable orcomputer-readable medium may be any apparatus that can tangibly store aprogram for use by or in connection with an instruction executionsystem, apparatus, or device. A medium may be an electronic, magnetic,optical, electromagnetic, infrared, semiconductor, or a combinationthereof, etc. system (or apparatus or device or article of manufacture).Examples of a computer-readable medium may include, but are not limitedto, a semiconductor or solid state memory, magnetic tape, a removablecomputer diskette, a random access memory (RAM), a read-only memory(ROM), a rigid magnetic disk, an optical disc, or a combination thereof.Examples of optical discs may include, but are not limited to, a compactdisc-read only memory (CD-ROM), a compact disc-read/write (CD-R/W),digital versatile disc (DVD), or a combination thereof. Acomputer-usable or computer-readable medium may includecomputer-readable memory devices, which may include any of the devicesor mediums discussed above, although it excludes signals, signaltransmission, and carrier waves. With regard to terminology, unlesscontext dictates otherwise, use herein of the word “or” may beconsidered use of an “inclusive or,” or a term that permits inclusion orapplication of one or more items that are linked by the word “or” (e.g.,a phrase “A or B” may be interpreted as permitting just “A,” permittingjust “B,” or permitting both “A” and “B”).

Although subject matter has been described in language specific tostructural features and/or methodological operations, it is to beunderstood that the subject matter defined in the appended claims is notnecessarily limited to the specific features or operations describedabove, including orders in which they are performed.

The invention claimed is:
 1. A first wireless communication devicecomprising: a transceiver configured to transmit a synchronizationbeacon in a neighbor awareness networking (NAN) environment, wherein theNAN environment includes a plurality of wireless communication devicesarranged in a cluster; and a synchronization beacon transmission systemconfigured to determine if the first wireless communication device isassociated with a synchronization role, and if the first wirelesscommunication device is determined to be associated with thesynchronization role, determine a transmission time based at leastpartially on an operation that separates the wireless communicationdevices of the cluster into multiple groups, and cause the transceiverto transmit the synchronization beacon responsive to the determinedtransmission time, and determine if the first wireless communicationdevice is associated with an anchor master role, and if the firstwireless communication device is determined to be associated with theanchor master role, cause the transceiver to transmit thesynchronization beacon substantially at a start time of a discoverywindow.
 2. The first wireless communication device of claim 1, wherein:the transceiver is further configured to transmit the synchronizationbeacon during the discovery window but after the start time if the firstwireless communication device is determined to be associated with thesynchronization role.
 3. The first wireless communication device ofclaim 1, wherein the wireless communication devices of the clusterinclude the first wireless communication device; and wherein: thetransceiver is further configured to transmit the synchronization beaconto facilitate temporal synchronization between or among the wirelesscommunication devices at least within the cluster of the NANenvironment.
 4. The first wireless communication device of claim 1,wherein the operation includes use of a hop count; and wherein: thesynchronization beacon transmission system is further configured todetermine the transmission time based at least partially on theoperation that uses the hop count.
 5. The first wireless communicationdevice of claim 1, wherein the operation includes use of a modulusoperator; and wherein: the synchronization beacon transmission system isfurther configured to determine the transmission time based at leastpartially on the operation that uses the modulus operator.
 6. The firstwireless communication device of claim 1, wherein the operationcomprises a hop count, corresponding to the first wireless communicationdevice, being subjected to a modulo operation with respect to a valuethat at least partially establishes a total number of groups for themultiple groups; and wherein: the synchronization beacon transmissionsystem is further configured to determine the transmission time based atleast partially on the operation that is at least partly dependent on(i) the hop count and (ii) the value.
 7. The first wirelesscommunication device of claim 1, wherein: the transceiver is furtherconfigured to receive a hop count value that is indicative of a hopcount of a second wireless communication device that is one hop closerto an anchor master device than the first wireless communication device,if the first wireless communication device is determined to beassociated with the synchronization role.
 8. The first wirelesscommunication device of claim 1, wherein the synchronization beaconcomprises a time indicator and a hop count indicator.
 9. The firstwireless communication device of claim 8, wherein the time indicatorcomprises a time stamp to facilitate a temporal synchronization of thecluster of the NAN environment.
 10. A method configured to beimplemented with a first wireless communication device, the methodcomprising: determining, in a neighbor awareness networking (NAN)environment that includes a plurality of wireless communication devicesarranged in a cluster, a transmission time based at least partially onan operation that separates the wireless communication devices of thecluster into multiple groups, the operation including assigning thefirst wireless communication device into a group of the multiple groupsbased at least partially on a received indicator of relative distancewith respect to at least a second wireless communication device of thewireless communication devices of the cluster; and transmitting asynchronization beacon in the NAN environment responsive to thedetermined transmission time.
 11. The method of claim 10, wherein thetransmission time comprises a time slot having a time range; and whereinthe determining comprises determining the time slot with the time slotto be shared by at least a third wireless communication device that isseparated into the group of the multiple groups.
 12. The method of claim10, wherein the transmission time comprises a relative offset time thatis at least partially dependent on a start time of a discovery window;and wherein the determining comprises determining the relative offsettime using the start time of the discovery window.
 13. The method ofclaim 10, wherein the received indicator of relative distance comprisesa hop count indicator.
 14. The method of claim 13, wherein thedetermining comprises determining the group of the multiple groups bymapping a hop count value of the hop count indicator to the group of themultiple groups.
 15. The method of claim 14, wherein the mappingcomprises modding the hop count value using a grouping characteristicindicative of a total number of groups for the multiple groups of thecluster.
 16. A computer-readable memory device comprisingcomputer-executable instructions that, when executed, implement a systemin a first wireless communication device to: determine, in a neighborawareness networking (NAN) environment that includes a plurality ofwireless communication devices arranged in a cluster, a transmissiontime based at least partially on an operation that separates thewireless communication devices of the cluster into multiple groups,including to obtain a grouping characteristic of the cluster, obtain ahop count for the first wireless communication device with respect to ananchor master for the cluster, and compute the transmission time for asynchronization beacon based at least partially on (i) the obtainedgrouping characteristic and (ii) the obtained hop count; and transmitthe synchronization beacon in the NAN environment responsive to thedetermined transmission time.
 17. The computer-readable memory device ofclaim 16, wherein to determine comprises to determine the transmissiontime so as to enable respective ones of the wireless communicationdevices that are separated into a same group of the multiple groups totransmit respective synchronization beacons at a same time.
 18. Thecomputer-readable memory device of claim 16, wherein to computecomprises to compute the transmission time at least partially inaccordance with Transmission Time=TStartDW+[((HC−1) %Z)+1]*40*aSlotTimeT, wherein “TStartDW” represents a start time of adiscovery window, “HC” represents the obtained hop count, “Z” representsthe obtained grouping characteristic, and “aSlotTimeT” represents alength of time to at least partially buffer consecutive synchronizationbeacons.
 19. The computer-readable memory device of claim 16, whereinthe synchronization beacon includes a time indicator that facilitatestemporal synchronization for at least some of the wireless communicationdevices of the cluster; and wherein to transmit comprises to transmitthe synchronization beacon that includes the time indicator.
 20. Thecomputer-readable memory device of claim 16, wherein the system in thefirst wireless communication device is further to: determine if thefirst wireless communication device is associated with a synchronizationrole; and transmit the synchronization beacon in the NAN environmentbased on a determination that the first wireless communication device isassociated with the synchronization role.